Many mobile operators sell phone service on shared operating plans (i.e., shared billing plans) where multiple phone lines are collected in a single account, for example a Family Plan in which each member of the family is associated with a particular phone line, and each line corresponds to one account for billing and service authorization purposes.
While mobile operators know the phone numbers on a shared plan, they often do not know much about the associated device and its holder. In particular, the operator often does not know the name of each device holder.